Telephone system.



E. LAND & F. L. FISHER.

TELEPHONB SYSTEM.

APPLICATION FILED MARA 22, 1906v 1 1 1 7,407, Patented Nov. 17, 1914.

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B. LAND & F. L. FISHER. TELEPHONB SYSTEM. APPLICATION FILED MAR. 22 1906. 1,1 1 7,4072 Patented Nov. 17, 1914.

Edmund Land; E L. E'z'shefl 21/1? z esses z Invenfons, ofmm 'Y w w ym/ E. LAND SL F. L. FISHER.

TELEPHONB SYSTEM.

APYLwATioN FILD MAR. 22, 1908.

1,1 17,407. Patented NOV.17,1914.

ECmundLana, I: L. 17.3.9120,` wz'nesses In ve n Z'brgf i ance of the-connection EDMUND LAND AND FRANK L.

MISNE ASSIGNMENTS, T0

FISHER, OF GRAND RAPIDS, MICHIGAN, ASSIG'NOB'S, BY

FREDERICK C. STEVENS, OF ATTICA, NEW YORK.

TELEPHONE SYSTEM,

Application filed March 22,

T0 all whom it may concern:

Be it known that we, EDMUND LAND, a subject of the King of Great Britain, and FRANK L. FISHER, a citizen of the United States of America, residents of Grand Rapids, county of Kent, and .State of Michigan, have invented a new and useful lmprovement in Telephone Systems, of which the following is a specification.

Our invention pertains to the automatic distribution of telephone calls coming into a central office, its function being that duty known as Y-switching. By Y-switching is meant the distribution of calls from telephone lines to a switchboard where the calls are to be completed, a Y-operator in manual practice having no communication with the patrons calling, but merely passing the calls to a switchboard operator, or A-operator for attention. The object is to distribute the incoming calls properly among the A- operators so that the total task of answering all calls may be distributed evenly throughout the line-connecting-board, or Ar-board This accomplishes an improvement in the quality of the service 'ven by the switchboard as a whole, or a ecrease in the cost of giving service, or both. The mechanical'reuirements, therefore, of Y-switching, cover thedistribution of calls from a large number of telephone lines toja smaller number of trunk lines, a calling line being connected to an idle trunk line and left in connection with that trunk until the call is completed.

Our invention consists'of a system whereby the Y-switching is done automatically, a group of trunks being assigned to a group of subscribers lines and automatic switches according to our' invention provided for connecting a calling line to an idle trunk, with the result that any calling line is connected to the first idle trunk line encountered by the operation and left connected to that trunk until thel call is completed, both the trunk line and the subscriberls line being so guarded by busy test conditions that neither is interrupted during the continufor conrersation.

The advance in our invention over the'y previous state of the art is that a Y-switch per trunk is provided instead of a Y-switch per line: inasmuch as the number of trunks. always is smaller than the number of lines, a resultant economy is effected.

Three figures accoinpany this specificaspecification of Letters Yatent.

sulated from each Patented Nov. 17, 1914.

1908. smar No. 807,818.

tion, of .which Figure 1', drawn on two sheets, Fig. 1aL and Fig. 1b, respectively, show e circuits of the system; Fig, 'shows assembly of a switch adapted' to thel'requirements of our system, and Fig. 3 shows the rotary shaft of the switch of Fig, 2.

It will be seen by Figs. 2 and 3, that 1 is a bank of fixed contacts in' threel'layers,

each layer being substantilly' a icr'n} 'lete circle with fixed contacts 'equalliy i'pad throughout the circle. 'thefentirfbadathus presentxng a cylindi'ca'tinnerf :from which the fixed contats "iiojt'f cdliteritric with this cylindrical'si`` si'' fheflift '2,

upon which is mounteiiltlieiratchethaving a number of teeth'e ualf tfo'thnumber of contact intervals inthe offikdcontacts. magnet 4 ngithllarniature'l; and pawl 6 is also so dispoedfiht the' pa errgages the ratchet 3 'aild'at eclrfatti'iabtion of the armature 5 theratchetfistepped forward one step. Radial'cohtct' 7,'8, 9 are attached to the sliaft,""insiilatedffromthe shaft and from each other` theserafdial'contacts being so designed 'are in contact respectively wi" fixed contacts of the threelayers', and' step from contact to contact'fin'the layersfas'the ratchet 3 is set forward sftfe'xbyi stepibythe action of the magnet 'ontzictffng, 10, ll, 1'2, are mounted'uponfthe'shiaftinother and tlishaft, and are connected respectively'to ,the radial contacts. Fixed brushes 13, 14, ;15, bear upon these contact rings, and thus'eletfztrical connection is made betweei'nwthe fixedrparts 18, ll, 15 and the movingpartf'z, 8,9; For convenience in reference,M the-fixed'contacts,

16, 16, 16, 16, maybe refi'redto' as waitmg contacts; the radial contacts 7, 8, 9,, as wlpers, und the magnt ias av motor magnet. In the Circuit '-di''afwir'1g,`:y l15, we have shown diagranunatically three such Y- swit'chec, the respective parts being labeled to correspond witlrthelabels ,given iiifFigs. 2 and 3. The banks of Twaitingnitaf'ct,'s are l, the indi'vidualcontact point'vinot being labeled the Qshaft'hriushes a'ndjcontact rings areomitt'ed frornthil diagram as lunnecess'ary detail, the conductoi' wiresfbeing` shown connected directlyfto`th e, w'ip'ers, 7, 8, 9, 7', 8', v9' 7, 8, 9";`the magnet are shown at i, i, i, armfatures'are lshown at but the pawls 'vaud rat'ch'et are 5, f) omitted as unnecessary to the diagram; the

h' the 'homologious shown three complete W, and X, each trunk of a Y-switch and relay as describedl above, a pair of condensers 19, 20, a pair of visual signals- 21,

22, a listening key 23, to I;which an operatorls telephone set is attached'in the usual manner, a ringing key 24,`[to'.which a ringing generator is attached" at' the outer contacts in the usual manner, and a conheeting plug 25. Any required number of similar trunks .may be provided in any installation. The number of lines served b a single trunk will be limited by. the number of contacts in a layer of waiting contacts. If this number were 100, there would be required a ratchet wheel of 100 teet v In Fig. 1*, we have shown the equipment of four lines, including the relay equipment which pertains to the lines, and also the multiple terminal equipment, the latter pertaining to jacks for manual connectionv at the connecting switchboard as well as "to waiting contacts for, automatic connection With Y-switches. Taking ifor example, line A; a line relay 26 and cutofl' relay 27 provided at A', the line thence extending into the multiple cables to which vare attached a plurality of calling jacks, as A2, A3, and also waiting contacts in a plurality of Y- switches, as V, VV, X. It is to be noted that 'one of the line-wires is normally interrupted at a contactof a relay, for example 27; but this is closed when a call is instituted.- The trunk plugs'25, etc., are

' adapted to connect With the calling used shall nected to jacks A2, B2, etc., and the operatorls circuit be adapted to detect a' 'busy test upon the multiple jacks in 'some convenient well known way.

In Fig. '1, a conductor is shown in doubledotted lines, constituting conductors 28, 28', 282, 283, 29, 29', 292, 293, ao, 31, 32, 82',ana 32",'all of which conductors are concerned in the function of selecting the next idle trunk and in causing that trunk to become active in selectin a calling line in the following manner: t will be noted that the entire Fig. 1 does not show a closed battery circuit; all movable parts are in their respectivepositions of rest. It will be noted that the double-dotted conductor 31 extends in multiple branches to all of the line equipments, A', B', C', D', and is separated from ground at those points by 'open relay contacts; also, that it extends in serles through the trunk equipments V, W, X, being conground through a magnet coil and a battery in the first of the trunk equipments. If, now, a patron at substation'A* takes the reeeiver from the hook of atele- 8, 40, 46, 27, ground; this it will be noted phone set of the usual central battery typa circuit will be closed from grounded batter through 33, 26, 34, 35, A4, 36, 37, groun energizing relay 26, and closing a circuit as follows: from grounded battery through 17 5, 38, 4,39, 31, 29, 28, 37, ground, energizing motor-magnet 4 and Stepping forward wipers 7, 8, 9; this circuit by energization of motor-magnet 4 breaks itself at 17, and thus the armature 5 of the motor magnet vibrates and advances the wipers 7, 8, 9, by steps until a circuit is found to interrupt the circuit over conductor 31, above described, which occurs when the wipers reach the calling line; at that time wiper 8 contacts with conductor 40, which extends to the armature of energized relay 26, and the circuit is found as follows: from grounded battery through 17, 5, 88, 4, 41, 42, 18, 48, 21, 44, 45,

gives current through the windings of relays i 4,18 and 27 ad through the winding of visual signal 21, the adjustment of relays 18 and 27 and the adjustment of visual signal 21 being such that these relays and that signal are energized and operated. The adjustment of relay 4 however is such that the current through conductor 41, reduced as it is by the resistance of the three series windings in elements 18, 21 and 27, is insufliciem. to overcome the armature tensions, and inasmuch as the operation of the armatures of relay 18 has interrupted the path through the conductor 39, the relay 4, which is the motor magnet of the device, does not attract its armature and remains inactive and the contact between its armature and the contact 17 remains closed. By the operation of relay 18, the circuit through conductor 39 to conductor 31 'is broken, and the Y- 105 switch of trunk equipment V stops with its trunk conductors in connection with `the conductors of the multiple pertaining to line A: By the energization of cut-oil` relay 27, the conductor v36 is connected to the con- 110.

ductor 46 and thus to conductor 40 and thus to the multiple of the line and 'to the trunk conductors through the contact 46 and 40; thus a new circuit is formed for the line conductors 35 and` 36, the return to ground being now through the winding of relay 27 instead of through conductor 37 as was-the case while waiting for the action-of theiY- switch. By the operation of the lower armature of relay 18, ground is connected '120 through conductors 47, 48, 7, 49, 50 to the test rings of the jacks A2, A3, thus preventing the line from being taken by an operator with a connecting plug. The calling line A, now is connected to manual switching means, such as the plug 25, situated before a telephone operator at a manual switchboard, and the visual signal, 21, associated with that plug, /is energized to attract the attention of the operator; the

' jack, as

`be rungby the ringing key operator then answers the call, using her listening key 23' in the usual manner, and coinpletes the connection as requested by the patron, and in any manner provided for in manual switchboards. If the line called for be, say, the line D, the plug 25 may be inserted into any multiple D3, of that line, placing the busy test condition of ground upon the test ring of all multiple jacks as well as upon the waiting contacts associated withv that line; the signal bell at the substation then may 24, the circuit being from grounded generator through tip of plug and over the line, back to ground at conductor 373. Upon the answering of the called station, relay 263 is energized, closing circuit from gi'ounded battery through 22, 51, 82, 58, 25, D3, 54, 55, 273, 56, ground, energizing Visual signal 22 to indicate to the operator that the called patron has answered. [T his results also in the energiation of vrelay 273, giving proper talking conditions to the called line.. It will be noted also that the operation of the upper arniature of the relay 18 has connected the conductor 31 to conductor 32, thereby extending that conductor into the Y-switch of trunk ectuipment NV, where the doubledotted cond'uctor system now finds grounded battery through a winding of the motormagiiet of tlie Y-switch of trunk equipment W. Truiik equipment 7, therefore, is the next trunk equipment in order for use, and it will respond to the call ofrthe next calling telephone line.

' In connection With the diagramn'iatic rep- V resentation of the Y-switch of trunk equippleted from iiient W, it Will be notcd that the Wipers 7', 8', 9', rest upon the waiting contacts of line C; this is inerely iiicidental, and would result from the use of the trunk by line C and no subsequent use of either the trunk or the line. rlflie trunk Wipers have no release or restoriiig niechanisins, and have no predcteriiiiiied normal position of rest` remaining u'liei'eyer they happen to be left after a conversation until required forV use else- Where, or until the line upon which they are restingr becoiiies busy.

Assunie now that vline B calls, relay 26' will be energized and motor circuit comgrounded battery through 17', 30, 29', 28', 37',

- ground; at the first step of the Wipers 7', 8', 9', theywill eiigage the busy line D, `wh en lthreecii'cuits will be completed upon reylease'of arniature 5' as z ground follouis First Circuit -extends from grounded battery through 17'. es', if., 88', 31, 80, 29', 28', second Circuit extends from grounded battery through 17', 5', 38', 4', 41', 57', 48', 7', 58, 59, D3, 25, 6G, ground; third circuit extends froiii grounded batterv through 17', 5', 38', 4', 41', 42', 18',

'relay 18 the connection'.between 48', 21', 44', 45', 8', 61, 62, 54, 55, 271, 56, ground. If, through this third cii'cuit the' relay 18' were energized to opera-te, the Y- switch of trunk equipment W would stop upon this busy line, but the current through that relay is very small owing to the factthat it is shunted by two other cii'cuits iiivolving relay 273 as parts thereof, viz: from gxrounded battery through ,3, 54,` 55, 27", 56, ground, and from grounded battery through 263, 35, substation, 363, 27, 56; the current flow through relay 18' therefore is insufficient lto -energize it to operate, operated by the combined currents through the two circuits, '-first eircuit and 'second circuit, above described, thus passing the trunk wipers over the busy lines Waiting contacts. The wipers so pass on around the switch, passiiig line A in inanner similar to the manner iii which line D Was passed, the difference being that line A is busy because it had called and line D is busy because it was called. The circiiits involved are as follows: First circuitexactly as above describedr as to D; second cii'cuit extends from grounded battery through 17', 38', 4', 41', 57', 48', 7', 49', 50, 49, 7, 48, 47,, ground; third circuit extendps'froni grtlnded battery through 17', 5',.38', 4', 41',:1'7', 18', 13', 21', 14', 45', 40', 40,46, 27'., ground; the sliunt circuits are from groundcd battery through 17, 5, 38, 4, 41,Y 42, .18, 43, 44, 45, 8, 40, 46, 2", ground, andfrom ground-sd battery through 83, 26, 34, 35, A*7, 256, 27, ground: tlius both classes of busy lines are passed, and the Y-s'witch of trunk equipment will stop in connection With the teriiiinals of the calling line B, and by energizing the relay 18' will connect the doubledotted conductor to link ,conductor 32',

'tliei'eby providing a Circuit extending from grounded battery through 17", 5, 38", 4, 39", 82', 82, 31, and thencebranching to all line equipinents, wliereby it is seen that the next calling line will causetrunk X equipment to operate a'nd to care for the call in the nianner already described for' trunk equipments V and VV.

WVheii the callingl subscriber, as at substatiou AJ, iaiigs up his teleplione, relay 26 Will be released, breaking the ciz'cuit which energizes relay 18, and by the release of the motor iiiagnet and the double-dotted system of coiiductors Will be restored, so that trunk V will take the next incoining call regardless of the condition of busy-ness orl idleness 'of trunk equipiiieiits 'Vfor ll' or others. lt has been iioted that trunkequipiiicnt VV has its wipcrs restiiig upon the waiting contacts of line C; if, now, line Cbecomes busy by being plugged into at one of its multiple jacks, the cs'ndition of busy test u'ill be manifest by I a ground upon its test and motor inagnet 4' is V ii o ilo

will wait until moved, either by reason of' i the line contacted with becoming busy or by reason of the trunk care for an incoming call. In case a second call is made by va given line, while the trunk office with the jacks be in separate central oflices or may be l -V equipment IV still has its wipers resting on the waiting contacts of that line, that trunk equipment will operate in the previously de- 'scribed' manner, except that it Will not rotate, but will immediately signal the operator and establish busy conditions. The plugs, 25, 25', 25", may be in the' same central A2, B2, etc., or they m y cated at Vseparate switchboards.

IVe have thus described fully our system of automatic Y-switching, and its manner of Operating; we do not wish to limit ourselves in all particulars to the details herein shown and described, as we know that many modifications and variations may be devised without departing from the spirit and scope of our invention.

IVhat we claim as new and desire to secure by United States Letters Patent is:

1. Ina telephone system, a plurality of telephone lines, multiple jacks forming multipled terminals for said telephone lines, trunks, Y-switches associated with said trunks, Sets of waiting contacts in said Y- switches forming additional multipled terminals for said telephone lines in multiple with the jack terminals of said telephone lines, wiping contacts in said Y-switches forming terminals of said trunks; switch plugs adaptcd to connect with said multiple jacks and forming terminals for said trunks at the ends distant from the wiping-contact terminals thcreof; means for placing a busytest condition upon the terminals of a telephone line by connection of trunk wiping contacts with any set of waiting contacts of that line; means for plcing busy-test conditicns upon the terminals of a telephone line by connection of a trunk plug with any jack of that line, motor mechanism for causin;r said wiping contacts to pass from set to set of said waiting contacts, and means for causing the operation of said motor mechanism, said means becoming operable when the wiping contacts of a non-busy trunk rest in contact with waitingl contacts of a non-busy line and said line has busy test conditions placed upon its terminals by reaitself being required to son of that line being connected With at some one of its by wiping 'contacts or by a switching plug.

2. In a telephone system, a Y-switch, a trunk terminating in the wipers of Said Y- switch, lines terminating` in Waiting contacts in said Y-switch, means for placing4 busy test conditions upon the waiting contacts of one of said telephone lines, motor mechanism for said wipers, and means causing said -motcr mechanism to. become active when busy test is placed upon the waiting con'- tacts of a line with which the Wipers of a. trunk are in electrical connection, substantially as described. i

3. In a telephone system, a telephone line, a line relay responsive to current changes in said line when calling, a plurality of trunks, automatic rotary Y-switches, one associated with each of said trunks, each adapted to connect its associated trunk to said telephone line when said telephone line is calling; an auxiliary relay associated with each Y- switch and a circuit adapted to be closed by control of the substation upon the line relay of said telephone line and extending through contacts of. the auxiliary relay to the first of said Y-switches, whereby, When said circuit is closed by the control of said telephone substation, said first of said Y-switches will respond and connect its associated trunk to said telephone line; said auxiliary switch Operating when said Y-switch connects With the telephone line, to connect said circuit to the second of the Y-switches, substantially as described.

4. In a telephone system, a telephone line,

a plurality of rotary Y-switches, a circuit adapted to be closed by control of said telephone line and extcnding to the first of said Y-switches, and a relay in the first of said Y-switches to extend such circuit to the second of said Y-switches, and a circuit including the winding of said Vrelay and'extending through the' line contacts of said automatic Y-switch and thence closed through the substation bridge of said line,

lwhen said first Y-switch has its wipers in connection with the waiting contacts of said line, substantially as described.v

5.' In a telephone system, a plurality of telephone lines, a plurality of line relays each associated with and adapted to be energized by closure of one of said telephone lines, a plurality of rot-ary Y-switches in each of which said telephone lines are connected to waiting contacts, a circuit adapted to be closed by control of the line relay becoming energized in response to a call from a substation upon any of said telephone lines and cxtending to the first of said Y-switches, and a relay in the first of said Y-switches to extend said circuit to the second of said Y-switches when said first Y-switch has its wipers in connection with the Waiting conmultipled terminals, either' tacts of a busy telephone line, substantially as described.

6. In a telephone systein, a plurality of telephone lines, a plurality of trunks, Y- switches, one associated with each of said trunks, and each adapted to connect its associated trunk to a calling oiie of said telephone lines,-line relays associated with said telephoiie lines, eacli adapted to become energized When its associated line circuit is closed in initiating a call, an auxiliary switching relay associated with each Y- switch and containing inake and break contacts, and a motor circiiit connected in multiple to contacts of said line relays, and thence to the shifting meinber of the make and break contacts in one of the said auxiliary-switdhing i'elays, with a branch motor circuit extending from the normally closed or break side of said relay contacts to the associated Y-swit'ches, and a second branch extending from the normally open or make side of said contacts to the auxiliary relay of another Y-sivtch, vwhereby when any line is calling said motoi` circuit will be closed by the line relay contact of the calling line causiiig the motor mechanism of the first Y-switch to operate, and means to energize the auxiliary relay of said switch When the line is found to break the normally closed motor contacts and close the norinally open contacts so as to shift the motor circuit to the next switch.

7. In a telephone system, a plurality of telephone lines, a plurality of ti'unks; Y- switches, one associated With each of said trunks and each adapted to connect its as-` sociated trunk to -a calling one of said telephone lines, line relays associated with said telephone lines, each becoming energized when its associated line circuit is closed, a

motoi` circuit exteiiding from a predetermined Y-switch and brancliing in niultiple to contacts of said line relays, Whereby, when any line is calling said motor circuit will be closed by a line relay contact of the calling' line causing the motor mechanismof the predetermined Y-sivitch to operate, and

a relay in the Operating Y-switch to extend any line is calling closed' by a line relay contact of the calling line causing the motor meclianism of said' said motor circuit to the motor mechanism of .another Y-switch Y-switch connects with the calling line, stantially as described.

8. In a telephone system, telephone lines, a plurality of trunks; Y- switches, one associated ii'ith each of said ti'unks and each adapted to connect its associated ti'unk to a calliiig one of said telephone lines, line relays associated With said telephone lines, each becoming energized when its associated line circuit is closed, a motor circuit extending from one of said Y-switches and branching in multiple to contacts of said line relays, whereby, when said motor circuit Will be suba plurality of Y-switch to operate, and a relay in each Y-switch for removing its motor mechanism from said motor circuit when the, Y-switch is busy, siibstantially as described.

9. In an exchange system, the combina tion with teleplione lines angl cord circuits for connecting the same, of. a plurality of switching mechanisins associated with the cord circuits, the telephone lines. being joined to a plurality of si'yitching mechanisms, a relay included in each -line and aiding'in the control of any one of .the plurality of switching mechanisms to which the line is joined, ual to each switching mechanism and being controlled by the connection through its switching mechanism of a cord circuit with an originating line, the transfer relay upon operation sei'ving to shift the capability of control by the relays of other lines terminating at its switching mechanism to other switching mechanisms, substantially as described and for the purposes set forth.

Signed by us at Grahd Rapids, county of Kent and State of Michigan, in the presence of two witnesses. a

EDMUND LAND. FRANK L. FISHER. lVitnesses:

J. CLYDE LARAWAY, A. V. HOFFMAN.

and a transfer relay individ-- when the Operating 

